Mrs. Baxter and Mrs. Herndon
5th Life Science
Bill Nye Genetics Video
Genetics
1. Genetics is the study of genes, heredity, and genetic variation in living organisms.
https://genetics of a four leaf clover
2. DNA (Deoxyribonucleic Acid) - carries the genetic information for a cell and is a set of instructions that tells the cell what to do or be.
3. Chromosome – a single long molecule of DNA (x shape).
https://brain pop DNA/
4. Gene – a part of the chromosome that contains DNA
Traits:
What are traits?
1. Traits are characteristics we
inherit from your parents.
2. The environment we grow up
and live in also helps define our
traits. For example: exposure to
chemicals or sunlight can change hair color
Genetic traits
5. Inherited trait – a characteristic passed from parents to their offspring. 6. Dominate trait – a strong trait that appears even if the organisms has only one factor. 7. Recessive trait – a trait that appears only if an organism has two factors. 8. Hidden trait – a trait that an organism carries, but is not expressed.
Dominant vs. Recessive Traits●9. Allele - one of a pair of genes that control a trait, such as blood type or colorblindness.
●Alleles are different “flavors of genes”●They will be either dominant or recessive traits
●There will always be 1 allele from the Mother and 1 allele from the Father
●a diagram called the Punnett Square●Punnett Square Video
More say of the outcome of that trait
No say unless there are 2 recessive alleles
What is Heredity?
10. Heredity - the passing on
of traits from parents to a child
We inherit traits from our parents
1. What traits have your inherited from your parents?
2. Why do brothers and sisters resemble each other?
DNA (“De-oxy-ribo-nucleic” Acid)Chemical code Master copy of instructions
for cell structure and function
Give us our traits like hair color, eye color, height, personality, & talents
Each gene makes proteins (building blocks for everything in your body)
DNA (“De-oxy-ribo-nucleic” Acid)Structure (what it looks
like) Three dimensional helix
Spiral staircase or
twisted ladder
Humans have 46 pairs
of chromosomes (or 23
pairs)
Half from one parent &
half from another parent
DNA Structure Cross pieces, “rungs” are
made of nitrogen base pairs
Same two bases always pair together:
adenine (A) & thymine (T)
cytosine (C) & guanine (G) The matching of the base
pairs, (A with T) and (C with G), provides a way for exact copies of DNA to be made called DNA replication.
DNA Mutation - Damaged chromosomes
- Mismatched base pairs
DNA Mutation - Mistakes in the DNA
- Example: albinism
DNA Discovery/History (1950-1960’s) - Rosalind Franklin 1st to
x-ray DNA
DNA X-rayRosalind Franklin
DNA Discovery/History (1950-1960’s) Maurice Wilkins gives Rosalind
Franklin’s x-rays to James Watson and Francis Crick
Crick and Watson make the 1st model of DNA
Rosalind Franklin dies of cancer
Wilkins, Watson, and Crick share a Nobel Prize for the DNA model
DNA Model
DNA Discovery/History (1950-1960’s)Maurice Wilkins
James Watson and Francis Crick
DNA Model Sketch